The concept of a blue economy, focused on the sustainable and regenerative use of ocean resources, has emerged as a strategic pathway for balancing economic growth, environmental protection, and social development, particularly for coastal communities. This transformation is essential to address the escalating economic and ecological challenges in these areas. As a maritime nation with significant natural advantages and a strategic geopolitical location, Vietnam’s pursuit of the blue economy requires effective engagement with a multilayered legal framework, comprising international law and its domestic legal system. This paper examines how existing international legal regimes, particularly under the 1982 United Nations Convention on the Law of the Sea, respond to the evolving demands of the blue economy and climate-responsive development. The paper also analyzes the international legal framework to identify key legal principles underpinning the blue economy, including the principle of sustainable development, intergenerational equity, equitable benefit-sharing, the no-harm principle, and the principle of international cooperation. These principles serve as foundational norms for guiding national legislation and international engagement in marine resource governance. By focusing on Vietnam’s legal system and policies, the study argues that realizing a sustainable blue economy demands not only legal reform but also improved inter-agency coordination, institutional consolidation, and international cooperation. The paper advocates for harmonizing national and international legal standards, and enhancing legal capacity for implementation. This approach supports Vietnam’s efforts to fulfill Sustainable Development Goal 14, reinforcing the need for inclusive and adaptive legal governance of the ocean in the era of the twin transition.